Black paste under emi shield

Hello, can't seem to find any information about this, so hopefully someone can help me.

A friend of mine washed her iPhone 6 in the washing machine. I've got an ultrasonic tank and some PCB cleaning solution so hopefully have some chance at repair.

When removing the emi shield from the a8 processor, there is a large amount of black paste under it. Just wondering if anyone knew what to replace this with when refitting, or should i not have removed it in the first place? I'm assuming it's there to dissipate heat, so do not really want to try it without!

Thanks for your reply. I'm used to applying thermal paste to CPU/heatsinks and i have some arctic silver for that. It just seemed like a lot for thermal paste, as I'm used to applying a really thin layer. I'm slightly concerned that it may seep out, so I'll look at the data sheets of some other pastes to see if there's any info available.

1 Answer

It is a thermal paste, so that the CPU shield is properly sinking any heat generated by the CPU. I would remove it prior to cleaning it otherwise it will dirty your (expensive) Branson EC solution for nothing.

When you're ready to re-assemble, apply some thermal paste of your own to insure good conduction. This particular paste appears to be based on carbon black, which is better than typical white/silicone pastes. Knowing Apple, they probably even designed their own exotic paste to get even more performance out (maybe @tomchai knows more).

At the very least, you need to apply some quality thermal paste of your own. As independent repair techs/shops, this is the best we can do.

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